Guideline for Hand Hygiene in Health-Care Settings

Transcription

1 Morbidity and Mortality Weekly Report Recommendations and Reports October 25, 2002 / Vol. 51 / No. RR-16 Guideline for Hand Hygiene in Health-Care Settings Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force INSIDE: Continuing Education Examination Centers for Disease Control and Prevention SAFER HEALTHIER PEOPLE TM

2 MMWR CONTENTS The MMWR series of publications is published by the Epidemiology Program Office, Centers for Disease Control and Prevention (CDC), U.S. Department of Health and Human Services, Atlanta, GA SUGGESTED CITATION Centers for Disease Control and Prevention. Guideline for Hand Hygiene in Health-Care Settings: Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. MMWR 2002;51(No. RR- 16):[inclusive page numbers]. Centers for Disease Control and Prevention Julie L. Gerberding, M.D., M.P.H. Director David W. Fleming, M.D. Deputy Director for Science and Public Health Dixie E. Snider, Jr., M.D., M.P.H. Associate Director for Science Epidemiology Program Office Stephen B. Thacker, M.D., M.Sc. Director Office of Scientific and Health Communications John W. Ward, M.D. Director Editor, MMWR Series Suzanne M. Hewitt, M.P.A. Managing Editor Rachel J. Wilson Douglas W. Weatherwax Project Editors Malbea A. Heilman Beverly J. Holland Visual Information Specialists Quang M. Doan Erica R. Shaver Information Technology Specialists Part I. Review of the Scientific Data Regarding Hand Hygiene... 1 Historical Perspective... 1 Normal Bacterial Skin Flora... 2 Physiology of Normal Skin... 2 Definition of Terms... 3 Evidence of Transmission of Pathogens on Hands... 4 Models of Hand Transmission... 5 Relation of Hand Hygiene and Acquisition of Health-Care Associated Pathogens... 5 Methods Used To Evaluate the Efficacy of Hand-Hygiene Products... 6 Review of Preparations Used for Hand Hygiene... 8 Activity of Antiseptic Agents Against Spore-Forming Bacteria Reduced Susceptibility of Bacteria to Antiseptics Surgical Hand Antisepsis Relative Efficacy of Plain Soap, Antiseptic Soap/Detergent, and Alcohols Irritant Contact Dermatitis Resulting from Hand-Hygiene Measures Proposed Methods for Reducing Adverse Effects of Agents Factors To Consider When Selecting Hand-Hygiene Products Hand-Hygiene Practices Among HCWs Lessons Learned from Behavioral Theories Methods Used To Promote Improved Hand Hygiene Efficacy of Promotion and Impact of Improved Hand Hygiene Other Policies Related to Hand Hygiene Hand-Hygiene Research Agenda Web-Based Hand-Hygiene Resources Part II. Recommendations Categories Recommendations Part III. Performance Indicators References Appendix Continuing Education Activity... CE-1

3 Vol. 51 / RR-16 Recommendations and Reports 1 Guideline for Hand Hygiene in Health-Care Settings Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force Prepared by John M. Boyce, M.D. 1 Didier Pittet, M.D. 2 1 Hospital of Saint Raphael New Haven, Connecticut 2 University of Geneva Geneva, Switzerland Summary The Guideline for Hand Hygiene in Health-Care Settings provides health-care workers (HCWs) with a review of data regarding handwashing and hand antisepsis in health-care settings. In addition, it provides specific recommendations to promote improved hand-hygiene practices and reduce transmission of pathogenic microorganisms to patients and personnel in health-care settings. This report reviews studies published since the 1985 CDC guideline (Garner JS, Favero MS. CDC guideline for handwashing and hospital environmental control, Infect Control 1986;7:231 43) and the 1995 APIC guideline (Larson EL, APIC Guidelines Committee. APIC guideline for handwashing and hand antisepsis in health care settings. Am J Infect Control 1995;23:251 69) were issued and provides an in-depth review of hand-hygiene practices of HCWs, levels of adherence of personnel to recommended handwashing practices, and factors adversely affecting adherence. New studies of the in vivo efficacy of alcohol-based hand rubs and the low incidence of dermatitis associated with their use are reviewed. Recent studies demonstrating the value of multidisciplinary hand-hygiene promotion programs and the potential role of alcohol-based hand rubs in improving hand-hygiene practices are summarized. Recommendations concerning related issues (e.g., the use of surgical hand antiseptics, hand lotions or creams, and wearing of artificial fingernails) are also included. Part I. Review of the Scientific Data Regarding Hand Hygiene Historical Perspective For generations, handwashing with soap and water has been considered a measure of personal hygiene (1). The concept of cleansing hands with an antiseptic agent probably emerged in the early 19 th century. As early as 1822, a French pharmacist demonstrated that solutions containing chlorides of lime or soda could eradicate the foul odors associated with human corpses and that such solutions could be used as disinfectants and antiseptics (2). In a paper published in 1825, this pharmacist stated that physicians and other persons attending patients with contagious diseases would benefit from moistening their hands with a liquid chloride solution (2). In 1846, Ignaz Semmelweis observed that women whose babies were delivered by students and physicians in the First Clinic at the General Hospital of Vienna consistently had a The material in this report originated in the National Center for Infectious Diseases, James M. Hughes, M.D., Director; and the Division of Healthcare Quality Promotion, Steve Solomon, M.D., Acting Director. higher mortality rate than those whose babies were delivered by midwives in the Second Clinic (3). He noted that physicians who went directly from the autopsy suite to the obstetrics ward had a disagreeable odor on their hands despite washing their hands with soap and water upon entering the obstetrics clinic. He postulated that the puerperal fever that affected so many parturient women was caused by cadaverous particles transmitted from the autopsy suite to the obstetrics ward via the hands of students and physicians. Perhaps because of the known deodorizing effect of chlorine compounds, as of May 1847, he insisted that students and physicians clean their hands with a chlorine solution between each patient in the clinic. The maternal mortality rate in the First Clinic subsequently dropped dramatically and remained low for years. This intervention by Semmelweis represents the first evidence indicating that cleansing heavily contaminated hands with an antiseptic agent between patient contacts may reduce health-care associated transmission of contagious diseases more effectively than handwashing with plain soap and water. In 1843, Oliver Wendell Holmes concluded independently that puerperal fever was spread by the hands of health personnel (1). Although he described measures that could be taken to limit its spread, his recommendations had little impact on

4 2 MMWR October 25, 2002 obstetric practices at the time. However, as a result of the seminal studies by Semmelweis and Holmes, handwashing gradually became accepted as one of the most important measures for preventing transmission of pathogens in health-care facilities. In 1961, the U. S. Public Health Service produced a training film that demonstrated handwashing techniques recommended for use by health-care workers (HCWs) (4). At the time, recommendations directed that personnel wash their hands with soap and water for 1 2 minutes before and after patient contact. Rinsing hands with an antiseptic agent was believed to be less effective than handwashing and was recommended only in emergencies or in areas where sinks were unavailable. In 1975 and 1985, formal written guidelines on handwashing practices in hospitals were published by CDC (5,6). These guidelines recommended handwashing with nonantimicrobial soap between the majority of patient contacts and washing with antimicrobial soap before and after performing invasive procedures or caring for patients at high risk. Use of waterless antiseptic agents (e.g., alcohol-based solutions) was recommended only in situations where sinks were not available. In 1988 and 1995, guidelines for handwashing and hand antisepsis were published by the Association for Professionals in Infection Control (APIC) (7,8). Recommended indications for handwashing were similar to those listed in the CDC guidelines. The 1995 APIC guideline included more detailed discussion of alcohol-based hand rubs and supported their use in more clinical settings than had been recommended in earlier guidelines. In 1995 and 1996, the Healthcare Infection Control Practices Advisory Committee (HICPAC) recommended that either antimicrobial soap or a waterless antiseptic agent be used for cleaning hands upon leaving the rooms of patients with multidrug-resistant pathogens (e.g., vancomycin-resistant enterococci [VRE] and methicillin-resistant Staphylococcus aureus [MRSA]) (9,10). These guidelines also provided recommendations for handwashing and hand antisepsis in other clinical settings, including routine patient care. Although the APIC and HICPAC guidelines have been adopted by the majority of hospitals, adherence of HCWs to recommended handwashing practices has remained low (11,12). Recent developments in the field have stimulated a review of the scientific data regarding hand hygiene and the development of new guidelines designed to improve hand-hygiene practices in health-care facilities. This literature review and accompanying recommendations have been prepared by a Hand Hygiene Task Force, comprising representatives from HICPAC, the Society for Healthcare Epidemiology of America (SHEA), APIC, and the Infectious Diseases Society of America (IDSA). Normal Bacterial Skin Flora To understand the objectives of different approaches to hand cleansing, a knowledge of normal bacterial skin flora is essential. Normal human skin is colonized with bacteria; different areas of the body have varied total aerobic bacterial counts (e.g., 1 x 10 6 colony forming units (CFUs)/cm 2 on the scalp, 5 x 10 5 CFUs/cm 2 in the axilla, 4 x 10 4 CFUs/cm 2 on the abdomen, and 1 x 10 4 CFUs/cm 2 on the forearm) (13). Total bacterial counts on the hands of medical personnel have ranged from 3.9 x 10 4 to 4.6 x 10 6 (14 17). In 1938, bacteria recovered from the hands were divided into two categories: transient and resident (14). Transient flora, which colonize the superficial layers of the skin, are more amenable to removal by routine handwashing. They are often acquired by HCWs during direct contact with patients or contact with contaminated environmental surfaces within close proximity of the patient. Transient flora are the organisms most frequently associated with health-care associated infections. Resident flora, which are attached to deeper layers of the skin, are more resistant to removal. In addition, resident flora (e.g., coagulase-negative staphylococci and diphtheroids) are less likely to be associated with such infections. The hands of HCWs may become persistently colonized with pathogenic flora (e.g., S. aureus), gramnegative bacilli, or yeast. Investigators have documented that, although the number of transient and resident flora varies considerably from person to person, it is often relatively constant for any specific person (14,18). Physiology of Normal Skin The primary function of the skin is to reduce water loss, provide protection against abrasive action and microorganisms, and act as a permeability barrier to the environment. The basic structure of skin includes, from outer- to innermost layer, the superficial region (i.e., the stratum corneum or horny layer, which is 10- to 20-µm thick), the viable epidermis (50- to 100-µm thick), the dermis (1- to 2-mm thick), and the hypodermis (1- to 2-mm thick). The barrier to percutaneous absorption lies within the stratum corneum, the thinnest and smallest compartment of the skin. The stratum corneum contains the corneocytes (or horny cells), which are flat, polyhedral-shaped nonnucleated cells, remnants of the terminally differentiated keratinocytes located in the viable epidermis. Corneocytes are composed primarily of insoluble bundled keratins surrounded by a cell envelope stabilized by cross-linked proteins and covalently bound lipid. Interconnecting the corneocytes of the stratum corneum are polar structures (e.g., corneodesmosomes), which contribute to stratum corneum cohesion.

5 Vol. 51 / RR-16 Recommendations and Reports 3 The intercellular region of the stratum corneum is composed of lipid primarily generated from the exocytosis of lamellar bodies during the terminal differentiation of the keratinocytes. The intercellular lipid is required for a competent skin barrier and forms the only continuous domain. Directly under the stratum corneum is a stratified epidermis, which is composed primarily of layers of keratinizing epithelial cells that are responsible for the synthesis of the stratum corneum. This layer also contains melanocytes involved in skin pigmentation; Langerhans cells, which are important for antigen presentation and immune responses; and Merkel cells, whose precise role in sensory reception has yet to be fully delineated. As keratinocytes undergo terminal differentiation, they begin to flatten out and assume the dimensions characteristic of the corneocytes (i.e., their diameter changes from µm to µm, and their volume increases by 10- to 20-fold). The viable epidermis does not contain a vascular network, and the keratinocytes obtain their nutrients from below by passive diffusion through the interstitial fluid. The skin is a dynamic structure. Barrier function does not simply arise from the dying, degeneration, and compaction of the underlying epidermis. Rather, the processes of cornification and desquamation are intimately linked; synthesis of the stratum corneum occurs at the same rate as loss. Substantial evidence now confirms that the formation of the skin barrier is under homeostatic control, which is illustrated by the epidermal response to barrier perturbation by skin stripping or solvent extraction. Circumstantial evidence indicates that the rate of keratinocyte proliferation directly influences the integrity of the skin barrier. A general increase in the rate of proliferation results in a decrease in the time available for 1) uptake of nutrients (e.g., essential fatty acids), 2) protein and lipid synthesis, and 3) processing of the precursor molecules required for skin-barrier function. Whether chronic but quantitatively smaller increases in rate of epidermal proliferation also lead to changes in skin-barrier function remains unclear. Thus, the extent to which the decreased barrier function caused by irritants is caused by an increased epidermal proliferation also is unknown. The current understanding of the formation of the stratum corneum has come from studies of the epidermal responses to perturbation of the skin barrier. Experimental manipulations that disrupt the skin barrier include 1) extraction of skin lipids with apolar solvents, 2) physical stripping of the stratum corneum using adhesive tape, and 3) chemically induced irritation. All of these experimental manipulations lead to a decreased skin barrier as determined by transepidermal water loss (TEWL). The most studied experimental system is the treatment of mouse skin with acetone. This experiment results in a marked and immediate increase in TEWL, and therefore a decrease in skin-barrier function. Acetone treatment selectively removes glycerolipids and sterols from the skin, which indicates that these lipids are necessary, though perhaps not sufficient in themselves, for barrier function. Detergents act like acetone on the intercellular lipid domain. The return to normal barrier function is biphasic: 50% 60% of barrier recovery typically occurs within 6 hours, but complete normalization of barrier function requires 5 6 days. Definition of Terms Alcohol-based hand rub. An alcohol-containing preparation designed for application to the hands for reducing the number of viable microorganisms on the hands. In the United States, such preparations usually contain 60% 95% ethanol or isopropanol. Antimicrobial soap. Soap (i.e., detergent) containing an antiseptic agent. Antiseptic agent. Antimicrobial substances that are applied to the skin to reduce the number of microbial flora. Examples include alcohols, chlorhexidine, chlorine, hexachlorophene, iodine, chloroxylenol (PCMX), quaternary ammonium compounds, and triclosan. Antiseptic handwash. Washing hands with water and soap or other detergents containing an antiseptic agent. Antiseptic hand rub. Applying an antiseptic hand-rub product to all surfaces of the hands to reduce the number of microorganisms present. Cumulative effect. A progressive decrease in the numbers of microorganisms recovered after repeated applications of a test material. Decontaminate hands. To Reduce bacterial counts on hands by performing antiseptic hand rub or antiseptic handwash. Detergent. Detergents (i.e., surfactants) are compounds that possess a cleaning action. They are composed of both hydrophilic and lipophilic parts and can be divided into four groups: anionic, cationic, amphoteric, and nonionic detergents. Although products used for handwashing or antiseptic handwash in health-care settings represent various types of detergents, the term soap is used to refer to such detergents in this guideline. Hand antisepsis. Refers to either antiseptic handwash or antiseptic hand rub. Hand hygiene. A general term that applies to either handwashing, antiseptic handwash, antiseptic hand rub, or surgical hand antisepsis. Handwashing. Washing hands with plain (i.e., non-antimicrobial) soap and water.

6 4 MMWR October 25, 2002 Persistent activity. Persistent activity is defined as the prolonged or extended antimicrobial activity that prevents or inhibits the proliferation or survival of microorganisms after application of the product. This activity may be demonstrated by sampling a site several minutes or hours after application and demonstrating bacterial antimicrobial effectiveness when compared with a baseline level. This property also has been referred to as residual activity. Both substantive and nonsubstantive active ingredients can show a persistent effect if they substantially lower the number of bacteria during the wash period. Plain soap. Plain soap refers to detergents that do not contain antimicrobial agents or contain low concentrations of antimicrobial agents that are effective solely as preservatives. Substantivity. Substantivity is an attribute of certain active ingredients that adhere to the stratum corneum (i.e., remain on the skin after rinsing or drying) to provide an inhibitory effect on the growth of bacteria remaining on the skin. Surgical hand antisepsis. Antiseptic handwash or antiseptic hand rub performed preoperatively by surgical personnel to eliminate transient and reduce resident hand flora. Antiseptic detergent preparations often have persistent antimicrobial activity. Visibly soiled hands. Hands showing visible dirt or visibly contaminated with proteinaceous material, blood, or other body fluids (e.g., fecal material or urine). Waterless antiseptic agent. An antiseptic agent that does not require use of exogenous water. After applying such an agent, the hands are rubbed together until the agent has dried. Food and Drug Administration (FDA) product categories. The 1994 FDA Tentative Final Monograph for Health-Care Antiseptic Drug Products divided products into three categories and defined them as follows (19): Patient preoperative skin preparation. A fast-acting, broadspectrum, and persistent antiseptic-containing preparation that substantially reduces the number of microorganisms on intact skin. Antiseptic handwash or HCW handwash. An antisepticcontaining preparation designed for frequent use; it reduces the number of microorganisms on intact skin to an initial baseline level after adequate washing, rinsing, and drying; it is broad-spectrum, fast-acting, and if possible, persistent. Surgical hand scrub. An antiseptic-containing preparation that substantially reduces the number of microorganisms on intact skin; it is broad-spectrum, fast-acting, and persistent. Evidence of Transmission of Pathogens on Hands Transmission of health-care associated pathogens from one patient to another via the hands of HCWs requires the following sequence of events: Organisms present on the patient s skin, or that have been shed onto inanimate objects in close proximity to the patient, must be transferred to the hands of HCWs. These organisms must then be capable of surviving for at least several minutes on the hands of personnel. Next, handwashing or hand antisepsis by the worker must be inadequate or omitted entirely, or the agent used for hand hygiene must be inappropriate. Finally, the contaminated hands of the caregiver must come in direct contact with another patient, or with an inanimate object that will come into direct contact with the patient. Health-care associated pathogens can be recovered not only from infected or draining wounds, but also from frequently colonized areas of normal, intact patient skin (20 31). The perineal or inguinal areas are usually most heavily colonized, but the axillae, trunk, and upper extremities (including the hands) also are frequently colonized (23,25,26,28,30 32). The number of organisms (e.g., S. aureus, Proteus mirabilis, Klebsiella spp., and Acinetobacter spp.) present on intact areas of the skin of certain patients can vary from 100 to 10 6 /cm 2 (25,29,31,33). Persons with diabetes, patients undergoing dialysis for chronic renal failure, and those with chronic dermatitis are likely to have areas of intact skin that are colonized with S. aureus (34 41). Because approximately 10 6 skin squames containing viable microorganisms are shed daily from normal skin (42), patient gowns, bed linen, bedside furniture, and other objects in the patient s immediate environment can easily become contaminated with patient flora (30,43 46). Such contamination is particularly likely to be caused by staphylococci or enterococci, which are resistant to dessication. Data are limited regarding the types of patient-care activities that result in transmission of patient flora to the hands of personnel (26,45 51). In the past, attempts have been made to stratify patient-care activities into those most likely to cause hand contamination (52), but such stratification schemes were never validated by quantifying the level of bacterial contamination that occurred. Nurses can contaminate their hands with 100 1,000 CFUs of Klebsiella spp. during clean activities (e.g., lifting a patient; taking a patient s pulse, blood pressure, or oral temperature; or touching a patient s hand, shoulder, or groin) (48). Similarly, in another study, hands were cultured of nurses who touched the groins of patients heavily colonized with P. mirabilis (25); CFUs/mL of this

7 Vol. 51 / RR-16 Recommendations and Reports 5 organism were recovered from glove juice samples from the nurses hands. Recently, other researchers studied contamination of HCWs hands during activities that involved direct patient-contact wound care, intravascular catheter care, respiratorytract care, and the handling of patient secretions (51). Agar fingertip impression plates were used to culture bacteria; the number of bacteria recovered from fingertips ranged from 0 to 300 CFUs. Data from this study indicated that direct patient contact and respiratory-tract care were most likely to contaminate the fingers of caregivers. Gram-negative bacilli accounted for 15% of isolates and S. aureus for 11%. Duration of patient-care activity was strongly associated with the intensity of bacterial contamination of HCWs hands. HCWs can contaminate their hands with gram-negative bacilli, S. aureus, enterococci, or Clostridium difficile by performing clean procedures or touching intact areas of the skin of hospitalized patients (26,45,46,53). Furthermore, personnel caring for infants with respiratory syncytial virus (RSV) infections have acquired RSV by performing certain activities (e.g., feeding infants, changing diapers, and playing with infants) (49). Personnel who had contact only with surfaces contaminated with the infants secretions also acquired RSV by contaminating their hands with RSV and inoculating their oral or conjunctival mucosa. Other studies also have documented that HCWs may contaminate their hands (or gloves) merely by touching inanimate objects in patient rooms (46,53 56). None of the studies concerning hand contamination of hospital personnel were designed to determine if the contamination resulted in transmission of pathogens to susceptible patients. Other studies have documented contamination of HCWs hands with potential health-care associated pathogens, but did not relate their findings to the specific type of preceding patient contact (15,17,57 62). For example, before glove use was common among HCWs, 15% of nurses working in an isolation unit carried a median of 1 x 10 4 CFUs of S. aureus on their hands (61). Of nurses working in a general hospital, 29% had S. aureus on their hands (median count: 3,800 CFUs), whereas 78% of those working in a hospital for dermatology patients had the organism on their hands (median count: 14.3 x 10 6 CFUs). Similarly, 17% 30% of nurses carried gramnegative bacilli on their hands (median counts: 3,400 38,000 CFUs). One study found that S. aureus could be recovered from the hands of 21% of intensive-care unit personnel and that 21% of physician and 5% of nurse carriers had >1,000 CFUs of the organism on their hands (59). Another study found lower levels of colonization on the hands of personnel working in a neurosurgery unit, with an average of 3 CFUs of S. aureus and 11 CFUs of gram-negative bacilli (16). Serial cultures revealed that 100% of HCWs carried gram-negative bacilli at least once, and 64% carried S. aureus at least once. Models of Hand Transmission Several investigators have studied transmission of infectious agents by using different experimental models. In one study, nurses were asked to touch the groins of patients heavily colonized with gram-negative bacilli for 15 seconds as though they were taking a femoral pulse (25). Nurses then cleaned their hands by washing with plain soap and water or by using an alcohol hand rinse. After cleaning their hands, they touched a piece of urinary catheter material with their fingers, and the catheter segment was cultured. The study revealed that touching intact areas of moist skin of the patient transferred enough organisms to the nurses hands to result in subsequent transmission to catheter material, despite handwashing with plain soap and water. The transmission of organisms from artificially contaminated donor fabrics to clean recipient fabrics via hand contact also has been studied. Results indicated that the number of organisms transmitted was greater if the donor fabric or the hands were wet upon contact (63). Overall, only 0.06% of the organisms obtained from the contaminated donor fabric were transferred to recipient fabric via hand contact. Staphylococcus saprophyticus, Pseudomonas aeruginosa, and Serratia spp. were also transferred in greater numbers than was Escherichia coli from contaminated fabric to clean fabric after hand contact (64). Organisms are transferred to various types of surfaces in much larger numbers (i.e., >10 4 ) from wet hands than from hands that are thoroughly dried (65). Relation of Hand Hygiene and Acquisition of Health-Care Associated Pathogens Hand antisepsis reduces the incidence of health-care associated infections (66,67). An intervention trial using historical controls demonstrated in 1847 that the mortality rate among mothers who delivered in the First Obstetrics Clinic at the General Hospital of Vienna was substantially lower when hospital staff cleaned their hands with an antiseptic agent than when they washed their hands with plain soap and water (3). In the 1960s, a prospective, controlled trial sponsored by the National Institutes of Health and the Office of the Surgeon General demonstrated that infants cared for by nurses who did not wash their hands after handling an index infant colonized with S. aureus acquired the organism more often and more rapidly than did infants cared for by nurses who used hexachlorophene to clean their hands between infant

8 6 MMWR October 25, 2002 contacts (68). This trial provided evidence that, when compared with no handwashing, washing hands with an antiseptic agent between patient contacts reduces transmission of health-care associated pathogens. Trials have studied the effects of handwashing with plain soap and water versus some form of hand antisepsis on healthcare associated infection rates (69,70). Health-care associated infection rates were lower when antiseptic handwashing was performed by personnel (69). In another study, antiseptic handwashing was associated with lower health-care associated infection rates in certain intensive-care units, but not in others (70). Health-care associated infection rates were lower after antiseptic handwashing using a chlorhexidine-containing detergent compared with handwashing with plain soap or use of an alcohol-based hand rinse (71). However, because only a minimal amount of the alcohol rinse was used during periods when the combination regimen also was in use and because adherence to policies was higher when chlorhexidine was available, determining which factor (i.e., the hand-hygiene regimen or differences in adherence) accounted for the lower infection rates was difficult. Investigators have determined also that health-care associated acquisition of MRSA was reduced when the antimicrobial soap used for hygienic handwashing was changed (72,73). Increased handwashing frequency among hospital staff has been associated with decreased transmission of Klebsiella spp. among patients (48); these studies, however, did not quantitate the level of handwashing among personnel. In a recent study, the acquisition of various health-care associated pathogens was reduced when hand antisepsis was performed more frequently by hospital personnel (74); both this study and another (75) documented that the prevalence of health-care associated infections decreased as adherence to recommended hand-hygiene measures improved. Outbreak investigations have indicated an association between infections and understaffing or overcrowding; the association was consistently linked with poor adherence to hand hygiene. During an outbreak investigation of risk factors for central venous catheter-associated bloodstream infections (76), after adjustment for confounding factors, the patient-to-nurse ratio remained an independent risk factor for bloodstream infection, indicating that nursing staff reduction below a critical threshold may have contributed to this outbreak by jeopardizing adequate catheter care. The understaffing of nurses can facilitate the spread of MRSA in intensive-care settings (77) through relaxed attention to basic control measures (e.g., hand hygiene). In an outbreak of Enterobacter cloacae in a neonatal intensive-care unit (78), the daily number of hospitalized children was above the maximum capacity of the unit, resulting in an available space per child below current recommendations. In parallel, the number of staff members on duty was substantially less than the number necessitated by the workload, which also resulted in relaxed attention to basic infection-control measures. Adherence to hand-hygiene practices before device contact was only 25% during the workload peak, but increased to 70% after the end of the understaffing and overcrowding period. Surveillance documented that being hospitalized during this period was associated with a fourfold increased risk of acquiring a health-care associated infection. This study not only demonstrates the association between workload and infections, but it also highlights the intermediate cause of antimicrobial spread: poor adherence to hand-hygiene policies. Methods Used To Evaluate the Efficacy of Hand-Hygiene Products Current Methods Investigators use different methods to study the in vivo efficacy of handwashing, antiseptic handwash, and surgical hand antisepsis protocols. Differences among the various studies include 1) whether hands are purposely contaminated with bacteria before use of test agents, 2) the method used to contaminate fingers or hands, 3) the volume of hand-hygiene product applied to the hands, 4) the time the product is in contact with the skin, 5) the method used to recover bacteria from the skin after the test solution has been used, and 6) the method of expressing the efficacy of the product (i.e., either percent reduction in bacteria recovered from the skin or log reduction of bacteria released from the skin). Despite these differences, the majority of studies can be placed into one of two major categories: studies focusing on products to remove transient flora and studies involving products that are used to remove resident flora from the hands. The majority of studies of products for removing transient flora from the hands of HCWs involve artificial contamination of the volunteer s skin with a defined inoculum of a test organism before the volunteer uses a plain soap, an antimicrobial soap, or a waterless antiseptic agent. In contrast, products tested for the preoperative cleansing of surgeons hands (which must comply with surgical handantisepsis protocols) are tested for their ability to remove resident flora from without artificially contaminating the volunteers hands. In the United States, antiseptic handwash products intended for use by HCWs are regulated by FDA s Division of Overthe-Counter Drug Products (OTC). Requirements for in vitro and in vivo testing of HCW handwash products and surgical

9 Vol. 51 / RR-16 Recommendations and Reports 7 hand scrubs are outlined in the FDA Tentative Final Monograph for Healthcare Antiseptic Drug Products (TFM) (19). Products intended for use as HCW handwashes are evaluated by using a standardized method (19). Tests are performed in accordance with use directions for the test material. Before baseline bacterial sampling and before each wash with the test material, 5 ml of a standardized suspension of Serratia marcescens are applied to the hands and then rubbed over the surfaces of the hands. A specified volume of the test material is dispensed into the hands and is spread over the hands and lower one third of the forearms. A small amount of tap water is added to the hands, and hands are completely lathered for a specified time, covering all surfaces of the hands and the lower third of the forearms. Volunteers then rinse hands and forearms under 40 º C tap water for 30 seconds. Ten washes with the test formulation are required. After the first, third, seventh, and tenth washes, rubber gloves or polyethylene bags used for sampling are placed on the right and left hands, and 75 ml of sampling solution is added to each glove; gloves are secured above the wrist. All surfaces of the hand are massaged for 1 minute, and samples are obtained aseptically for quantitative culture. No neutralizer of the antimicrobial is routinely added to the sampling solution, but if dilution of the antimicrobial in the sampling fluid does not result in demonstrable neutralization, a neutralizer specific for the test formulation is added to the sampling solution. For waterless formulations, a similar procedure is used. TFM criteria for efficacy are as follows: a 2-log 10 reduction of the indicator organism on each hand within 5 minutes after the first use, and a 3-log 10 reduction of the indicator organism on each hand within 5 minutes after the tenth use (19). Products intended for use as surgical hand scrubs have been evaluated also by using a standardized method (19). Volunteers clean under fingernails with a nail stick and clip their fingernails. All jewelry is removed from hands and arms. Hands and two thirds of forearms are rinsed with tap water (38 º C 42 º C) for 30 seconds, and then they are washed with a nonantimicrobial soap for 30 seconds and are rinsed for 30 seconds under tap water. Baseline microbial hand counts can then be determined. Next, a surgical scrub is performed with the test formulation using directions provided by the manufacturer. If no instructions are provided with the formulation, two 5-minute scrubs of hands and forearms followed by rinsing are performed. Reduction from baseline microbial hand counts is determined in a series of 11 scrubs conducted during 5 days. Hands are sampled at 1 minute, 3 hours, and 6 hours after the first scrubs on day 1, day 2, and day 5. After washing, volunteers wear rubber gloves; 75 ml of sampling solution are then added to one glove, and all surfaces of the hands are massaged for 1 minute. Samples are then taken aseptically and cultured quantitatively. The other glove remains on the other hand for 6 hours and is sampled in the same manner. TFM requires that formulations reduce the number of bacteria 1 log 10 on each hand within 1 minute of product application and that the bacterial cell count on each hand does not subsequently exceed baseline within 6 hours on day 1; the formulation must produce a 2-log 10 reduction in microbial flora on each hand within 1 minute of product application by the end of the second day of enumeration and a 3-log 10 reduction of microbial flora on each hand within 1 minute of product use by the end of the fifth day when compared with the established baseline (19). The method most widely used in Europe to evaluate the efficacy of hand-hygiene agents is European Standard (EN 1500 Chemical disinfectants and antiseptics. Hygienic hand-rub test method and requirements) (79). This method requires test volunteers and an 18- to 24-hour growth of broth culture of E. coli K12. Hands are washed with a soft soap, dried, and then immersed halfway to the metacarpals in the broth culture for 5 seconds. Hands are removed from the broth culture, excess fluid is drained off, and hands are dried in the air for 3 minutes. Bacterial recovery for the initial value is obtained by kneading the fingertips of each hand separately for 60 seconds in 10 ml of tryptic soy broth (TSB) without neutralizers. The hands are removed from the broth and disinfected with 3 ml of the hand-rub agent for 30 seconds in a set design. The same operation is repeated with total disinfection time not exceeding 60 seconds. Both hands are rinsed in running water for 5 seconds and water is drained off. Fingertips of each hand are kneaded separately in 10 ml of TSB with added neutralizers. These broths are used to obtain the final value. Log 10 dilutions of recovery medium are prepared and plated out. Within 3 hours, the same volunteers are tested with the reference disinfectant (60% 2- propanol [isopropanol]) and the test product. Colony counts are performed after 24 and 48 hours of incubation at 36 º C. The average colony count of both left and right hand is used for evaluation. The log-reduction factor is calculated and compared with the initial and final values. The reduction factor of the test product should be superior or the same as the reference alcohol-based rub for acceptance. If a difference exists, then the results are analyzed statistically using the Wilcoxon test. Products that have log reductions substantially less than that observed with the reference alcohol-based hand rub (i.e., approximately 4 log 10 reduction) are classified as not meeting the standard. Because of different standards for efficacy, criteria cited in FDA TFM and the European EN 1500 document for establishing alcohol-based hand rubs vary (1,19,79). Alcohol-based

10 8 MMWR October 25, 2002 hand rubs that meet TFM criteria for efficacy may not necessarily meet the EN 1500 criteria for efficacy (80). In addition, scientific studies have not established the extent to which counts of bacteria or other microorganisms on the hands need to be reduced to minimize transmission of pathogens in healthcare facilities (1,8); whether bacterial counts on the hands must be reduced by 1 log 10 (90% reduction), 2 log 10 (99%), 3 log 10 (99.9%), or 4 log 10 (99.99%) is unknown. Several other methods also have been used to measure the efficacy of antiseptic agents against various viral pathogens (81 83). Shortcomings of Traditional Methodologies Accepted methods of evaluating hand-hygiene products intended for use by HCWs require that test volunteers wash their hands with a plain or antimicrobial soap for 30 seconds or 1 minute, despite the observation in the majority of studies that the average duration of handwashing by hospital personnel is <15 seconds (52,84 89). A limited number of investigators have used 15-second handwashing or hygienic hand-wash protocols (90 94). Therefore, almost no data exist regarding the efficacy of plain or antimicrobial soaps under conditions in which they are actually used by HCWs. Similarly, certain accepted methods for evaluating waterless antiseptic agents for use as antiseptic hand rubs require that 3 ml of alcohol be rubbed into the hands for 30 seconds, followed by a repeat application for the same duration. This type of protocol also does not reflect actual usage patterns among HCWs. Furthermore, volunteers used in evaluations of products are usually surrogates for HCWs, and their hand flora may not reflect flora found on the hands of personnel working in health-care settings. Further studies should be conducted among practicing HCWs using standardized protocols to obtain more realistic views of microbial colonization and risk of bacterial transfer and cross-transmission (51). Review of Preparations Used for Hand Hygiene Plain (Non-Antimicrobial) Soap Soaps are detergent-based products that contain esterified fatty acids and sodium or potassium hydroxide. They are available in various forms including bar soap, tissue, leaflet, and liquid preparations. Their cleaning activity can be attributed to their detergent properties, which result in removal of dirt, soil, and various organic substances from the hands. Plain soaps have minimal, if any, antimicrobial activity. However, handwashing with plain soap can remove loosely adherent transient flora. For example, handwashing with plain soap and water for 15 seconds reduces bacterial counts on the skin by log 10, whereas washing for 30 seconds reduces counts by log 10 (1). However, in several studies, handwashing with plain soap failed to remove pathogens from the hands of hospital personnel (25,45). Handwashing with plain soap can result in paradoxical increases in bacterial counts on the skin (92,95 97). Non-antimicrobial soaps may be associated with considerable skin irritation and dryness (92,96,98), although adding emollients to soap preparations may reduce their propensity to cause irritation. Occasionally, plain soaps have become contaminated, which may lead to colonization of hands of personnel with gram-negative bacilli (99). Alcohols The majority of alcohol-based hand antiseptics contain either isopropanol, ethanol, n-propanol, or a combination of two of these products. Although n-propanol has been used in alcohol-based hand rubs in parts of Europe for many years, it is not listed in TFM as an approved active agent for HCW handwashes or surgical hand-scrub preparations in the United States. The majority of studies of alcohols have evaluated individual alcohols in varying concentrations. Other studies have focused on combinations of two alcohols or alcohol solutions containing limited amounts of hexachlorophene, quaternary ammonium compounds, povidone-iodine, triclosan, or chlorhexidine gluconate (61,93, ). The antimicrobial activity of alcohols can be attributed to their ability to denature proteins (120). Alcohol solutions containing 60% 95% alcohol are most effective, and higher concentrations are less potent ( ) because proteins are not denatured easily in the absence of water (120). The alcohol content of solutions may be expressed as percent by weight (w/w), which is not affected by temperature or other variables, or as percent by volume (vol/vol), which can be affected by temperature, specific gravity, and reaction concentration (123). For example, 70% alcohol by weight is equivalent to 76.8% by volume if prepared at 15 º C, or 80.5% if prepared at 25 º C (123). Alcohol concentrations in antiseptic hand rubs are often expressed as percent by volume (19). Alcohols have excellent in vitro germicidal activity against gram-positive and gram-negative vegetative bacteria, including multidrug-resistant pathogens (e.g., MRSA and VRE), Mycobacterium tuberculosis, and various fungi ( , ). Certain enveloped (lipophilic) viruses (e.g., herpes simplex virus, human immunodeficiency virus [HIV], influenza virus, respiratory syncytial virus, and vaccinia virus) are susceptible to alcohols when tested in vitro (120,130,131) (Table 1). Hepatitis B virus is an enveloped virus that is somewhat less susceptible but is killed by 60% 70% alcohol; hepatitis C virus also is likely killed by this percentage of alcohol (132). In a porcine tissue carrier model used to study antiseptic activity, 70% ethanol and 70% isopropanol were found to

11 Vol. 51 / RR-16 Recommendations and Reports 9 TABLE 1. Virucidal activity of antiseptic agents against enveloped viruses Ref. no. Test method Viruses Agent Results (379) Suspension HIV 19% EA LR = 2.0 in 5 minutes (380) Suspension HIV 50% EA LR > % IPA LR > 3.7 (381) Suspension HIV 70% EA LR = 7.0 in 1 minute (382) Suspension HIV 70% EA LR = 3.2B 5.5 in 30 seconds (383) Suspension HIV 70% IPA/0.5% CHG LR = 6.0 in 15 seconds 4% CHG LR = 6.0 in 15 seconds (384) Suspension HIV Chloroxylenol Inactivated in 1 minute Benzalkonium chloride Inactivated in 1 minute (385) Suspension HIV Povidone-iodine Inactivated Chlorhexidine Inactivated (386) Suspension HIV Detergent/0.5% Inactivated in 30 seconds PCMX (387) Suspension/dried plasma HBV 70% IPA LR = 6.0 in 10 minutes chimpanzee challenge (388) Suspension/plasma HBV 80% EA LR = 7.0 in 2 minutes chimpanzee challenge (389) Suspension HSV 95% EA LR > 5.0 in 1 minute 75% EA LR > % IPA LR > % EA + 0.5% CHG LR > 5.0 (130) Suspension RSV 35% IPA LR > 4.3 in 1 minute 4% CHG LR > 3.3 (141) Suspension Influenza 95% EA Undetectable in 30 seconds Vaccinia 95% EA Undetectable in 30 seconds (141) Hand test Influenza 95% EA LR > 2.5 Vaccinia 95% EA LR > 2.5 Note: HIV = human immunodeficiency virus, EA = ethanol, LR = Log 10 reduction, IPA = isopropanol, CHG = chlorhexidine gluconate, HBV = hepatitis B virus, RSV = respiratory syncitial virus, HSV = herpes simplex virus, HAV = hepatitis A virus, and PCMX = chloroxylenol. reduce titers of an enveloped bacteriophage more effectively than an antimicrobial soap containing 4% chlorhexidine gluconate (133). Despite its effectiveness against these organisms, alcohols have very poor activity against bacterial spores, protozoan oocysts, and certain nonenveloped (nonlipophilic) viruses. Numerous studies have documented the in vivo antimicrobial activity of alcohols. Alcohols effectively reduce bacterial counts on the hands (14,121,125,134). Typically, log reductions of the release of test bacteria from artificially contaminated hands average 3.5 log 10 after a 30-second application and log 10 after a 1-minute application (1). In 1994, the FDA TFM classified ethanol 60% 95% as a Category I agent (i.e., generally safe and effective for use in antiseptic handwash or HCW hand-wash products) (19). Although TFM placed isopropanol 70% 91.3% in category IIIE (i.e., insufficient data to classify as effective), 60% isopropanol has subsequently been adopted in Europe as the reference standard against which alcohol-based hand-rub products are compared (79). Alcohols are rapidly germicidal when applied to the skin, but they have no appreciable persistent (i.e., residual) activity. However, regrowth of bacteria on the skin occurs slowly after use of alcohol-based hand antiseptics, presumably because of the sublethal effect alcohols have on some of the skin bacteria (135,136). Addition of chlorhexidine, quaternary ammonium compounds, octenidine, or triclosan to alcohol-based solutions can result in persistent activity (1). Alcohols, when used in concentrations present in alcoholbased hand rubs, also have in vivo activity against several nonenveloped viruses (Table 2). For example, 70% isopropanol and 70% ethanol are more effective than medicated soap or nonmedicated soap in reducing rotavirus titers on fingerpads (137,138). A more recent study using the same test methods evaluated a commercially available product containing 60%

12 10 MMWR October 25, 2002 TABLE 2. Virucidal activity of antiseptic agents against nonenveloped viruses Ref. no. Test method Viruses Antiseptic Result (390) Suspension Rotavirus 4% CHG LR < 3.0 in 1 minute 10% Povidone-Iodine LR > % IPA/0.1% HCP LR > 3.0 (141) Hand test Adenovirus 95% EA LR > 1.4 Poliovirus 95% EA LR = Coxsackie 95% EA LR = Finger test Adenovirus 95% EA LR > 2.3 Poliovirus 95% EA LR = Coxsackie 95% EA LR = 2.9 (389) Suspension ECHO virus 95% EA LR > 3.0 in 1 minute 75% EA LR < % IPA LR = 0 70% IPA + 0.5% CHG LR = 0 (140) Finger pad HAV 70% EA 87.4% reduction 62% EA foam 89.3% reduction plain soap 78.0% reduction 4% CHG 89.6% reduction 0.3% Triclosan 92.0% reduction (105) Finger tips Bovine n-propanol + IPA LR = 3.8 in 30 seconds Rotavirus 70% IPA LR = % EA LR = 2.9 2% triclosan LR = 2.1 water (control) LR = % povidone-iodine LR = 1.3 plain soap LR = 1.2 4% CHG LR = 0.5 (137) Finger pad Human 70% IPA 98.9% decrease in 10 seconds Rotavirus plain soap 77.1% (138) Finger pad Human 70% IPA 99.6% decrease in 10 seconds Rotavirus 2% CHG 80.3% plain soap 72.5% (81) Finger pad Rotavirus 60% EA gel LR > 3.0 in 10 seconds Rhinovirus 60% EA gel LR > 3.0 Adenovirus 60% EA gel LR > 3.0 (139) Finger pad Poliovirus 70% EA LR = 1.6 in 10 seconds 70% IPA LR = 0.8 (200) Finger tips Poliovirus Plain soap LR = % EA LR = 0.4 Note: HIV = human immunodeficiency virus, EA = ethanol, LR = Log 10 reduction, IPA = isopropanol, CHG = chlorhexidine gluconate, HBV = hepatitis B virus, RSV = respiratory syncitial virus, HSV = herpes simplex virus, and HAV = hepatitis A virus. ethanol and found that the product reduced the infectivity titers of three nonenveloped viruses (i.e., rotavirus, adenovirus, and rhinovirus) by >3 logs (81). Other nonenveloped viruses such as hepatitis A and enteroviruses (e.g., poliovirus) may require 70% 80% alcohol to be reliably inactivated (82,139). However, both 70% ethanol and a 62% ethanol foam product with emollients reduced hepatitis A virus titers on whole hands or fingertips more than nonmedicated soap; both were equally as effective as antimicrobial soap containing 4% chlorhexidine gluconate in reducing reduced viral counts on hands (140). In the same study, both 70% ethanol and the 62% ethanol foam product demonstrated greater virucidal activity against poliovirus than either non-antimicrobial soap or a 4% chlorhexidine gluconate-containing soap (140). However, depending on the alcohol concentration, the amount of time that hands are exposed to the alcohol, and viral variant, alcohol may not be effective against hepatitis A and other nonlipophilic viruses. The inactivation of nonenveloped viruses is influenced by temperature, disinfectant-virus volume ratio, and protein load (141). Ethanol has greater activity against viruses than isopropanol. Further in vitro and in vivo studies of both alcohol-based formulations and antimicrobial soaps are warranted to establish the minimal level of virucidal activity that is required to interrupt direct contact transmission of viruses in health-care settings.